Simple Ac line Voltage Announcer Circuit Diagram

This is the Simple Ac line Voltage Announcer Circuit Diagram. The range
of this simple ac-voltage monitor is 100 to 140 Vac, with a resolution
of 1 V. The speech processor interprets an 8-bit binary input code from
an analog-to-digital converter. The processor`s pulse-code-mod ulated
output then passes through a filter and an amplifier before driving tbe
circuit`s speaker to vocalize the corresponding number. Each time switch
S1 is _pressed, the speech-processor program enun ciates tbe monitored
voltage readings from 100 to 140 V, depending on the code at the input
of a 27C64 EPROM.

Simple Ac line Voltage Announcer Circuit Diagram

The voltage-monitoring circuit consists of a bridge rectifier, filter
capacitors, and a 10-Kilload resis tor. A divider, RA and RB, limits the
input voltage to a maximum 2.55 V. The aid converter, IC4, then sends
the voltage reading to tbe 27C64 EPROM, ICS. Pressing Sl sends a
negative transient pulse to the write, WR, input of the aid converter,
IC4, which initiates a 100-ttS conversion process. [Link]